What is the relation between the the planes a1x + b1y + c1z + d1 = 0 and a2x + b2y + c21z + d2 = 0, if their normal are parallel to each other?

( frac {c1}{a2} = frac{b1}{b2} = frac{a1}{c2} )

( frac {a1}{b1} = frac{a2}{c1} = frac{c2}{b2} )

( frac {a1}{a2} = frac{b1}{c2} = frac{c1}{b2} )

( frac {a1}{a2} = frac{b1}{b2} = frac{c1}{c2} )

( frac {c1}{a2} = frac{b1}{b2} = frac{a1}{c2} )

What is the relation between the the planes a1x + b1y + c1z + d1 = 0 a

1.	What is the relation between the the planes a₁x + b₁y + c₁z + d₁ = 0 and a₂x + b₂y + c2₁z + d₂ = 0, if their normal are parallel to each other?
A.	( frac {a1}{b1} = frac{a2}{c1} = frac{c2}{b2} )
B.	( frac {a1}{a2} = frac{b1}{c2} = frac{c1}{b2} )
C.	( frac {a1}{a2} = frac{b1}{b2} = frac{c1}{c2} )
D.	( frac {c1}{a2} = frac{b1}{b2} = frac{a1}{c2} )
Answer» D. ( frac {c1}{a2} = frac{b1}{b2} = frac{a1}{c2} )